On March 22, 2016, in Tyson Foods, Inc. v. Bouaphakeo, the US Supreme Court held that a representative sample may be used to establish classwide liability for class certification ( (U.S. Mar. 22, 2016)).

Tyson's pork processing plant requires employees to wear protective gear, and compensates some, but not all, of the employees for donning and doffing (putting on and taking off) their gear. Respondents filed suit in the US District Court for the Northern District of Iowa, alleging that donning and doffing were integral and indispensable to their hazardous work and that Tyson's failure to pay for time spent on these activities denied them overtime compensation under the Fair Labor Standards Act (FLSA) and Iowa wage law. The respondents sought certification of their Iowa law claims under FRCP 23 and their federal claims as a collective action under the FLSA.

The district court granted class certification. To recover overtime compensation under the FLSA, the employees must show that they worked more than 40 hours a week including time spent donning and doffing. Since Tyson did not keep records of this time, the respondents primarily relied on a study by an industrial relations expert in which he conducted videotaped observations and analyzed how long various donning and doffing activities took. The jury awarded the class about $2.9 million in unpaid wages. The Eighth Circuit affirmed the judgment and award.

The Supreme Court held that the district court did not err in certifying the class. To certify a class under FRCP 23(b)(3), a court must find that questions of law or fact common to class members predominate over any questions affecting individual members. Tyson argued that the individual inquiries into how much time each worker spent donning and doffing predominate. The Supreme Court disagreed, and concluded that individual inquiries are unnecessary using the expert's representative sample.

The Supreme Court noted that whether and when statistical evidence can be used to establish classwide liability will depend on the purpose for which the evidence is introduced and the underlying cause of action. In some cases, a representative sample may be the only feasible way to establish liability. The representative sample here may prove classwide liability because the representative sample filled an evidentiary gap created by Tyson's failure to keep adequate records. Therefore, each class member would have likely relied on the representative sample to prove his hours worked in an individual action. (Anderson v. Mt. Clemens Pottery Co., 328 U. S. 680 (1946).) In FLSA actions, inferring the hours an employee has worked from such a study is permitted if the study is admissible.